I don't believe Figments should be seen as a classification, it's just a book of work. If you want to see a good summary of Winogrand's work, it's the place to go. The shots Winogrand never saw himself are marked as such, and not that strong, but I understand their inclusion.
As a focussed monogram I think Animals would be best, but I have not bought it yet because of prices. 1964 is the most intriguing as is color work is the least known.
I don't think of Winogrand as a 'book photographer' though. Any organisation of his work into a tightly defined subject seems superficial. You just got to take it all in and figure out the patterns by yourself.